Contrast media are used in medical settings to enhance the visibility of bodily structures during imaging procedures. Contrast media can highlight features that would otherwise be less distinguishable from nearby tissue to help a clinician diagnose and treat a patient's medical condition. A patient is typically injected with a contrast medium before or during an imaging procedure and then exposed to radiation or electromagnetic energy to generate an image of the patient's body. Example imaging techniques include X-ray, computed tomography (CT), nuclear magnetic resonance (NMR)/magnetic resonance (MR), ultrasound, fluoroscopy, and positron emission tomography (PET).
As an example, angiography is a medical procedure that usually involves injecting a patient with a contrast medium. Angiography is a procedure used in the diagnosis and treatment of cardiovascular conditions including abnormalities or restrictions in blood vessels. During angiography, a radiographic image of the heart or a vascular structure is obtained by injecting a radiographic contrast medium through a catheter into a vein or artery. The injected contrast medium can pass to vascular structures in fluid communication with the vein or artery in which the injection is made. X-rays are then passed through the region of the body in which the contrast material was injected. The X-rays are absorbed by the contrast medium, causing a radiographic outline or image of the blood vessel containing the contrast material.
When used, a contrast medium is typically injected into a patient by an automated injection system. While the apparatus for injecting the contrast medium can vary, most systems include a syringe operatively connected with a catheter. The catheter is placed into a vein or artery of a patient. During operation, a ram forces the contrast medium out of the syringe, through the catheter, and into the patient at a rate and volume determined by the speed of movement of the ram.
To ensure that an automated injection system is working properly prior to being placed in service and even after being placed in service, a contrast medium may be periodically passed through the injection system without actually injecting the contrast medium into a patient. Rather, the contrast medium may be passed through the injection system to monitor and validate the operational integrity of the injection system without injecting the contrast medium into a patient. For example, the fluid integrity of various fluid reservoirs, fluid lines, and connectors may be monitored during a test injection to ensure that there are no leaks in the injection system. The contrast medium discharged from an injection system during such operational testing is typically discarded after use.
Medical contrast media are generally expensive to manufacture and chemically stable once discarded. For example, some medical contrast media may pass through waste water treatment plants without decomposing. Ensuring that medical injection systems can be accurately tested and validated while limiting consumption of contrast media to medical procedures may provide a variety of benefits.